1.?主語從句如果表達的是一個事實，一般由that引導(dǎo)。that在從句中無詞義，不充當句子成分，僅起引導(dǎo)作用。如：
That?she?was?chosen?made?us?very?happy.?她被選上了，我們很高興。
That?the?earth?goes?round?the?sun?is?known?to?us?all.

2.?由whether引導(dǎo)的主語從句，表示“是否”之意，注意不能用if。
Whether?she?will?come?or?not?is?still?a?question.
他能否來還是個問題。
It?is?doubtful?whether?he?will?be?able?to?come.
她能否來令人懷疑。

3.?由疑問詞引導(dǎo)的主語從句，從句中要用陳述語序。如：
What?should?be?done?has?been?done.
應(yīng)該做的事情都做了。
What?we?need?is?more?time.
我們所需要的是更多的時間。
When?we?shall?have?our?sports?meet?is?still?a?question.
=?It?is?still?a?question?when?we?shall?have?our?sports?meet.
什么時候開運動會還是個問題。
What?he?did?is?not?yet?known.
=?It?is?not?yet?known?what?he?did.
他干了什么還不清楚。

4.?whatever，whoever，whichever等引導(dǎo)的主語從句。（注意不能轉(zhuǎn)化成it作形式主語的句型）。如：
Whatever?was?said?here?must?be?kept?secret.?這兒無論說的什么事都必須保密。
Whoever?breaks?the?law?will?be?punished.?無論誰犯了法都要受到懲罰。
Whichever?you?choose?is?fine?with?me.無論你選哪個我都無所謂。

5.?常見句型
1）由“It?is?+?adj.?+?that…”構(gòu)成的主語從句。
It?is?certain?that?we?shall?be?late.?我們肯定要遲到了。
It’s?strange?that?he?didn’t?come?yesterday.?真奇怪他昨天沒來。

2）由“It?is?+?n.?+?that…”構(gòu)成的主語從句。
It?is?a?pity?that?you?didn’t?see?the?film?yesterday.
It?is?a?wonder?that?he?refused?such?a?good?offer.

3）由“It?is?+?過去分詞?+?that…”構(gòu)成的主語從句。
It?is?reported?that?the?sports?meet?has?been?put?off.
據(jù)報道運動會推遲了。
It?has?not?been?decided?that?when?and?where?we?will?hold?the?meeting.
什么時候，在哪里開會還沒有決定。

4）由“It?+?不及物動詞?+?that…”構(gòu)成的主語從句。
It?turns?out?that?he?has?never?been?there.
原來他根本沒去過那兒。
It?occurred?to?her?that?she?might?as?well?talk?it?over?with?him.?她想起不妨去和和他談?wù)勥@件事。